During normal operation many electronic components generate significant amounts of heat. If this heat is not continuously removed the electronic component may overheat resulting in damage and/or a reduction in operating performance. In order to avoid such problems cooling devices are often used in conjunction with these components.
One such cooling device is a fan assisted heatsink. In such a device a heatsink is formed from a material, such as aluminum, which readily conducts heat. The heatsink is usually placed on top of and in physical contact with the component.
One method of increasing the cooling capacity of these heatsinks is by including a plurality of cooling fins that are physically connected to the heatsink. These fins serve to increase the surface area of the heatsink and, thus maximize the transfer of heat from the heatsink to the surrounding atmosphere. In this manner the heatsink draws heat away from the component and transfers the heat into the surrounding air.
In order to further enhance the cooling capacity of a heatsink device an electrically powered blower (an axial fan may serve as the blower) is often mounted within or on top of the heatsink. In operation the fan forces air to move past the fins of the heatsink, thus cooling the fins by enhancing the transfer of heat from the fins into the surrounding atmosphere. As air flows by the fins, heat can be drawn from the component into the heatsink at a faster rate. The fan typically draws air into the heatsink from the top, passes the air over the fins, and exhausts the air in the vicinity of the bottom. Accordingly, the exhaust air is hotter than that of the intake air.
There are known devices of this type, for example, U.S. Pat. No. 6,196,300 “Heatsink”. The device described in this U.S. patent comprises an axial fan that produces a flow passing by heat exchanging channels of the heatsink. The majority of inlets to the heat exchanging channels are located just opposite the axial fan's impeller with a certain number of said channels being placed radially in relation to the fan axle.
The axial fan produces a sufficiently air pressure. However, due to the weak airflow in the area adjacent to fan axle, the conditions for cooling the central part of the heatsink located underneath the fan are unfavorable. In this case non-uniform cooling of the heatsink and electronic component will take place allowing for bad conditions for the heat exchange process.
Centrifugal blowers are used more rarely in cooling device designs for the purpose of producing airflow.
Specifically, U.S. Pat. No. 5,838,066 “Miniaturized cooling fan type heatsink for semiconductor device” offers a design employing a centrifugal blower that is installed to the side of the heatsink. In one particular embodiment of this invention the cooling airflow passes by rectilinear means through the heat exchanging channels of the heatsink.
However, placement of a centrifugal blower to the side of the heatsink increases the devices size and reduces its effectiveness. This is because the location of the centrifugal blower leads to insufficient coordination between the direction of channel inlets and direction of airflow supplied from the blower. The loss in airflow energy results in the reduction of airflow speed in the heat exchanging channels and the reduction of heat exchange efficiency. A portion of energy is also expended as friction against the casing that encloses the blower.
An invention described in Japanese patent No. 8-195456 entitled “Cooler for electronic apparatus” discloses a centrifugal fan enclosed in a casing and installed above the heat exchanging channels which are divergent. Another heatsink surface is made so that the possibility of thermal contact with an electronic component is provided for. The inlet of the centrifugal fan faces the heatsink. The fan produces an airflow that passes by the heat exchanging channels and then gets drawn into the inlet of the centrifugal fan. Since this centrifugal fan operates by drawing air in through the heatsink, there is an area in the central part of the heatsink that receives poor air circulation. Adding to this problem, the airflow first passes through the elongated heat exchanging channels gathering heat along the way from the channels surfaces. As the air approaches the central part of the heatsink its cooling ability is decreased due to the reduced temperature differential between the preheated channel air temperature and the surface temperature at the center of the heatsink. This results in inefficient cooling of the heatsink's central surface area and uneven cooling of the heatsink in general. This is the area where the electronic component is transferring the most heat to the heatsink and where the greater differential between the two is most important. To help correct this problem, one has to increase the fans power resulting in an increased airflow but not solving the initial problem. In addition to the heat dissipation problems, the device is considerably larger due to the centrifugal fans placement above the heatsink. An electric drive also is yet placed above the centrifugal fan increasing the coolers overall size even more.
Additionally methods of producing these conventional coolers are very complicated because the heatsinks, the fans and the electric drives are produced separately.
It would be desirable to provide a cooling apparatus that would overcome these problems associated with the present fan assisted heatsink devices by producing an integrated apparatus, which serves all these disparate functions.